Well, I had an idea today in dealing with heating the pool more efficiently using the natural rise of warmer medium through colder ones... Basically, what about using the main drain as a hot-water return instead of the return fittings?

I did some diagrams and using simple 3-way and 2-way valves to accomplish this, I figured a 4-way vane-type valve would be needed to simplify this and started looking it up to find it just doesn't exist. What I did find is a methodology of exactly what I was thinking and it was a patented set of valves and design that used the main drain as a return, with the ball-returns and skimmer used as the intake (basically it takes warmer water from the top of the pool, heats it via the heater and returns it via the main drain allowing for better mixing and overall better thermal balance throughout the substrate) and as long as you are using a solar cover, the idea is you can achieve max-efficiency which would mean a total expenditure of about only 1/3 of what it costs doing it "normally"...

Now, I am not sure you can achieve an almost 70% increase in efficiency, but overall I have no doubt you cause a better mix and an increase of a certain amount of efficiency (probably less than 10-15% overall), but in general I am wondering if it is worth the expense of implementing this type of setup?

I would have to imagine using the main drain as the source of water would gain at least half the efficiency increase (purely by causing a better overall mix), but is there anyone with any valid input on the pros/cons???